TEST CATALOG ORDERING & RESULTS SPECIMEN HANDLING CUSTOMER SERVICE EDUCATION & INSIGHTS
Test Catalog

Test ID: OVSRP    
OXA-48-like (blaOXA-48-like) and VIM (blaVIM) Surveillance, PCR, Varies

Useful For Suggests clinical disorders or settings where the test may be helpful

Identifying carriers of Gram-negative bacilli harboring OXA-48-like (oxacillin-hydrolyzing beta-lactamase) or VIM (Verona integron-encoded metallo-beta-lactamase) genes

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

In the United States, Klebsiella pneumoniae carbapenemase (KPC) is the most common carbapenemase, followed by New Delhi metallo-beta-lactamase (NDM). OXA-48-like and VIM carbapenemases predominate in other parts of the globe, but do occur in the United States. The genes blaOXA-48-like and blaVIM encode OXA-48-like and VIM enzyme production, respectively. PCR is a sensitive, specific, and rapid means of identifying these genes.

 

This test detects the genes encoding OXA-48-like (oxacillin-hydrolyzing beta-lactamase) and VIM (Verona integron-encoded metallo-beta-lactamase) types of beta-lactamases in feces and perirectal/rectal/perianal/anal swabs. It can be used as a tool to find colonized patients. The Centers for Disease Control and Prevention recommends surveillance to detect unrecognized colonized patients who may be a potential source for transmission of carbapenemase-producing Gram-negative bacilli under certain circumstances. Such surveillance may be focused in certain high-risk settings or patient groups (eg, ICUs, long-term care facilities, patients transferred from areas or facilities with a high prevalence of the relevant type of resistance) or may be directed by infection prevention and control to investigate an outbreak.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Not applicable

Interpretation Provides information to assist in interpretation of the test results

This PCR assay detects and differentiates blaOXA-48-like and blaVIM in surveillance specimens (perirectal/rectal/perianal/anal swabs or feces). A positive OXA-48-like (oxacillin-hydrolyzing beta-lactamase) and/or VIM (Verona integron-encoded metallo-beta-lactamase) PCR indicates that the patient is colonized by a Gram-negative bacillus (or Gram-negative bacilli) harboring blaOXA-48-like and/or blaVIM, respectively. A negative result indicates the absence of detectable DNA.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

False-negative results may occur due to inhibition of PCR, sequence variability underlying primers and probes, or the presence of the blaOXA-48-like or blaVIM genes in quantities lower than the limit of detection of the assay.

Supportive Data

The assay was validated using 46 Gram-negative bacilli, including 30 carbapenemase-producers (26 OXA/VIM-type, 1 NMC/IMI, 1 NDM-1, and 2 KPC), and 2 Gram-positive organisms. The assay provided 100% sensitivity and specificity for both targets.

 

The assay detects OXA-48-like and VIM in surveillance perirectal/rectal/perianal/anal swabs and stool with the following limits of detection: OXA-48-like and VIM, 78 and 75 CFU/mL, respectively. A blinded panel of spiked perirectal/rectal/perianal/anal surveillance swabs and stool was assayed. The assay had 100% sensitivity and specificity, for both targets, in all spiked clinical samples.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Fernandez J, Cunningham SA, Fernandez-Verdugo A, et al: Evaluation of a real-time PCR assay for rectal screening of OXA-48-producing Enterobacteriaceae in a general intensive care unit of an endemic hospital. Diagnostic Microbiology and Infectious Disease 2017 July;88(3):252-258 doi.org/10.1016/j.diagmicrobio.2017.04.001

2. Bush K, Fisher JF: Epidemiological expansion, structural studies, and clinical challenges of new beta-lactamases from gram-negative bacteria. Annual Review of Microbiology 2011;65:455-478

3. Poirel L, Potron A, Nordmann P: OXA-48-like carbapenemases: the phantom menace. Journal of Antimicrobial Chemotherapy 2012;67:1597-1606

4. Nordmann P, Naas T, Poirel L: Global spread of carbapenemase-producing Enterobacteriaceae. Emerging Infectious Diseases 2011;17:1791-1798